Ceilings that separate occupied areas of a building from an attic area residing above the ceiling serve to reduce heat loss and associated energy costs by providing a trapped region of air in the attic space that serves as an insulator. The reduction of heat loss can be increased by covering the ceiling with an insulating material. However, when a hatch is installed in the ceiling to provide access to the attic space, the hatch interrupts the ceiling and can allow increased air infiltration between the occupied areas and the attic, reducing the insulating properties of the ceiling. This reduction in insulation of the ceiling is exacerbated when additional insulating material is placed on the ceiling, as this additional material must be removed from the area overlying the hatch.
One approach to limiting air infiltration and providing insulation over the area occupied by the hatch, when the hatch opens downwardly, is to place a cap of insulating material over the hatch opening, as taught in U.S. Pat. Nos. 4,151,894; 4,281,743; 4,312,423; 4,344,505; 4,541,208; 4,550,534; 4,591,022; 4,658,555; 4,832,153; 4,928,441; 5,271,198; 5,274,966; 5,481,833; 5,628,151; 5,867,946; and Re. 369,975; and in published applications U.S. 20020190070 and U.S. 20020112409. These caps are bulky and may be difficult for a user to reinstall properly when exiting the attic space.
An alternative approach for downwardly-opening hatches is to provide insulation on a door of the hatch, and to configure the door to seal against a frame to prevent air infiltration. This approach is taught in U.S. Pat. Nos. 4,299,059; 4,563,845; and 4,738,054. While these hatches provide ease of use, the thickness of insulation that can be provided on the doors of these hatches is very limited, particularly when the door also serves as a support for fold-down stairs. Even when such stairs are not employed, the thickness of insulation is limited since the insulation extends into and partially obstructs the hatch opening when the door hangs open.
A further limitation to all these downwardly-opening hatches is that there is no structure for holding back surrounding insulating material when additional insulating material has been placed on the ceiling. This requires the thickness of the insulating material in the region surrounding the hatch opening to be reduced, reducing the overall effectiveness of the additional insulating material.
The problems of limited hatch insulation and reduced thickness of insulating material around the hatch opening have been partially overcome for upwardly-opening trap doors, as taught in U.S. Pat. No. 4,944,126. The '126 patent teaches the construction of a box or guard around the hatch opening to hold back loose insulating material, in combination with a harness for securing insulating material to the trap door, which is lifted out of the opening to provide access. While the thickness of the insulating material on the door is not limited as with downwardly opening hatches, the insulating material must be spaced from the box or guard sufficiently to allow the user to lift and replace the door without binding. Thus, the insulating material cannot reside in close proximity to the box or guard for a substantial portion of its height, creating gaps in the insulating material. Furthermore, even if binding of the insulating material attached to the door is avoided, the lift-out trap door may still be difficult for the user to reinstall to close the opening. Another lift-out trap door is taught in U.S. Pat. No. 6,223,490, which teaches a lift-out door configured to engage a sleeve to provide an improved seal against air infiltration. However, the thickness of insulation of the '490 door appears to be very limited, and reinstallation of the door may again be difficult.
Thus, there is a need for an insulated ceiling hatch which overcomes the deficiencies of the devices discussed above.